It's unclear exactly why AT&T made the decision to do this, but many seem to suggest that AT&T is trying to "smoke out" users clinging to unlimited plans and force them to more lucrative [for AT&T] Mobile Share data plans.

Clearly, this won't sit well with the FCC, which will likely see this as an anticompetitive move. Nonprofit group Public Knowledge has already said that AT&T is violating the FCC's Open Internet Rules, which state that carrier's can't restrict customers from using applications that compete with their own "voice or video telephony services."

“There is no technical reason why one data plan should be able to access FaceTime and another not,” said John Bergmayer, a senior staff lawyer for Public Knowledge.

Mark Sigel, a spokesman for AT&T, countered the accusations by reiterating, “FaceTime is available to all of our customers today over Wi-Fi, and we’re now expanding its availability even further as an added benefit of our new Mobile Share data plans.”

Apple reportedly plans to announce its next-generation iPhone, which will pack the iOS 6 mobile operating system, on September 12. It will likely be released shortly thereafter, but for the new iPhones running on AT&T's network, it remains to be seen what will happen with this FaceTime issue.